With constructions like this, we can omit the article. However, they do have a particular tone to them which I admit I am struggling to describe. A few example sentences follow and I'm hoping a fellow native might be able to explain what it is about them that makes the omission possible!
Gradually, James changed from pupil to teacher.
Over the year, Jane transformed herself from ugly duckling to beautiful swan.
We have watched Gok Wan go from simple designer's assistant to fashion guru extraordinaire.
I'd like to go from fattest guy on the block, to skinniest dude in the neighbourhood.